Aqueous dispersion for chemical mechanical polishing, and chemical mechanical polishing method

Abstract

A chemical mechanical polishing aqueous dispersion includes colloidal silica (A), an anionic water-soluble polymer (B), and at least one type of an alkanolamine salt (C) selected from the group consisting of an alkyl sulfate and an alkyl ether sulfate, the chemical mechanical polishing aqueous dispersion having a pH of 1 to 4.

1 . A chemical mechanical polishing aqueous dispersion, comprising:
 colloidal silica (A),   an anionic water-soluble polymer (B), and   at least one an alkanolamine salt (C) selected from a group consisting of an alkyl sulfate and an alkyl ether sulfate,   wherein the chemical mechanical polishing aqueous dispersion has a pH of 1 to 4.   
     
     
         2 . The chemical mechanical polishing aqueous dispersion according to  claim 1 , wherein an alkyl sulfate moiety or an alkyl ether sulfate moiety included in the alkanolamine salt (C) has an alkyl chain having 8 to 20 carbon atoms. 
     
     
         3 . The chemical mechanical polishing aqueous dispersion according to  claim 1 , wherein a content of the alkanolamine salt (C) is 0.01 to 0.6 mass %. 
     
     
         4 . The chemical mechanical polishing aqueous dispersion according to  claim 1 , wherein a content of the anionic water-soluble polymer (B) is 0.005 to 0.15 mass %. 
     
     
         5 . A method, comprising polishing with the chemical mechanical polishing aqueous dispersion of  claim 1 . 
     
     
         6 . The method of  claim 7 , wherein a polishing rate of the tungsten film is equal to or more than four times a polishing rate of the silicon nitride film. 
     
     
         7 . The method of  claim 5 , wherein the polishing target comprises a tungsten film and a silicon nitride film. 
     
     
         8 . The method of  claim 7 , wherein an alkyl sulfate moiety or an alkyl ether sulfate moiety included in the alkanolamine salt (C) has an alkyl chain having 8 to 20 carbon atoms. 
     
     
         9 . The method of  claim 7 , wherein a content of the alkanolamine salt (C) is 0.01 to 0.6 mass %. 
     
     
         10 . The method of  claim 7 , wherein a content of the anionic water-soluble polymer (B) is 0.005 to 0.15 mass %. 
     
     
         11 . The method  claim 7 , wherein the polishing target consists of a tungsten film and a silicon nitride film. 
     
     
         12 . The method of  claim 11 , wherein a polishing rate of the tungsten film is equal to or more than four times a polishing rate of the silicon nitride film.